Fuel injection apparatus for internal combustion engines



Feb. 21, 1939. JA PUURMANN 'FUEL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed 0G12. 28, 1935 J kkomegs.

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Patented Feb. 21, '1939 FUEL INJECTION APPARATUS FOR IN- TERNAL COMBUSTION ENGINES Juri Puurmann, Paris, France Application October 28, i935, Serial No. 47,17l

In France October 3l, 193i Claims.

This invention has for its object improvements in and relating to fuel injecting pumps permit ting the use of pistons and cylinders having no asymmetrical slots, whereby irregular wear is done 5 away with; a. precise control of the stroke of the pump piston as well as the lubrication of the said I organs with cil; and also permitting thereby the use of a light fuel having no inherent lubricating properties.

lin the appended drawing there is shown, by vvay of example, a piston injecting pump with device for adjusting the stroke of the pump.

In the said dlavvinir Figure l is a cross sectional view of the pump.

Fig. 2 is `a cross-sectional view of the device for adjusting the stroke of the pump piston.

liig. 3 is a plan view of the adjusting device. Fig. t is a profile view of the actuating lever. Fig. 5 is a plan View ofthe lever of Fig. t. filig. 6 is a vievir of the lateral adjusting lever oi the link.

Fig. l is a plan view of the lateral lever of lillig. d.

it is the pump piston, it the cylinder, it the return spring, it the fuel inlet, lli the suction valve, it the discharge valve, it the discharge passage, tt the lubricating oil inlet, ti the circular oil passage, tt the oil hole in the cylinder, tt are the circular oil grooves in the piston, tt is the non-return valve body and tt the non-return valve for the lubricating oil.

The pump comprises one or more cylinders it. The piston receives a reciprocating movement from a cam il 'by means oi the levers t-t, .a pusher it, and the return spring it.

rlhe adjusting device comprises two-levers 5 and It. The first lever t is secured to the pump body at one of its ends by means of a stud l. Its other end is also provided With a pin tu carrying a roller t following the cam t of the pump.

To this pin 4c is secured the second lever t, the second end of `vvl'iich remains free. This second lever t is located` between the bearing point of the pusher of the piston rod it (or of the piston llt in the case when there is no pusher) and a ledge (itl or t6) which is movable and serves as a variable fulcruni. rlhis fulcrum (it or it) is adjustable along the second lever ii and rests on the pump body; thus it serves to change ou the amplitudes of oscillation of this lever t and also to vary the stroke of the piston i3 between il and its maximum.

During rotation the cam t Works, by means of the roller t and of the lever 5, on the pusher I2, which raises the piston I3 of the pump. An end of the lever t is secured to the stud 'i on which it freely turns. The middle line of this stud is fast with respect to the pump body. On the said stud or on another suitable axis can be also ixed the cranks t, which are connected, by means 5 of links 9, with the ledge it serving as a variable fulcrum. On. the stud l is also fixed the lever Ill (Figure 3) which is connected With the governor of the engine or With the gas pedal.' When the stud. 'i is turned it changes the position of the l0 variable fulcrum ill by means of the crank il and of the links t, the axis being brought farther from or nearer to the axis of the pump piston.

When the fulcrum airis lies in the middle line of the pump piston, as shown in Figure 1, the lever t being raised by the cam .t by means of th' roller t, the said lever only rocks about the variable fulcrum it and raises neither the pusher it nor the pump 'piston it.

As the fulcrum it moves farther from the o@ middle line of the piston, the lever 5 begins to rise and to raise the piston it! of the pump. When the fulcrum reaches its utmost position, as shown in Figure 2, the stroke of the `pump piston reaches its maximum. This stroke is i shown in broken lines in Figure 2. Thus, it is possible to adjust the stroke of the pump piston with precision by turning the stud l' through which 'the variable fulcrum lil on which the lever t rests is brought nearer to or farther from the middle line of the pump piston. This device causes no resistance at the governor, since friction is reduced to a minimum.

By controlling the fuel discharge through a variation of the piston stroke, a very short stroke is obtained for the pump piston, thus permitting the pump to rotate at a very great velocity.

Another feature of the invention relates to the lubrication of the piston and the cylinder. With an oil lubrication under pressure or without pressure for the cylinders and the pistons a more complete tightness is obtained for the pump and the said cylinders and pistons are protected against wear. The pressure of the lubricating oil can be selected greater than the pressure of the fuel. When the pressure of the lubricating oil is greater than the pressure of the fuel, the utmost security for the tightness of the pump is obtained. Under normal conditions it is possible to work with a low pressure for the lubricating oil or even at atmospheric pressure. .il particular device for lubrication under pressure is described in my divisional application.

The lubricating oil is introduced through. a double coupling 24 (Figure l.) provided with a non-return valve 2l. The oil which iills the circular lubrication passages absolutely opposes a flow 4of fuel and simultaneously lubricates the pistons and cylinders of the pump.

Of course, the invention, which has been described as applied to a fuel injecting pump, can

ybe also applied to all kinds of pumps for any liquid or even for gases. 4

The invention is also applicable to the various valves forexplosionengines, Diesel engines, turbines and'other prime movers or movable pieces. The above described device for varying the piston stroke can be used also for varying the stroke lof the valves of any engine cylinders by adjusting the same in relation with the other characteristics of the engines, such as suction, scavenging, exhaust and the like. X

In a like manner, the adjusting device for adjusting the piston' stroke can be used also for adjusting the stroke of other members such as, for instance, valves or moving mechanical pieces actuated by the rotation of a cam.

Lastly lt is also possible, of course, without departing from the spirit of the invention, to add edly connected to the first-mentioned lever.

2. A mechanism according to claim 1, in which the joint connection between the two levers carries means driven by the cam.

3. A variable stroke mechanism comprising a rotary cam, a lever rocked by said cam, a driven member freely bearing on one side of said lever at the middle thereof, a fulcrum member bearing on the opposite side of saidlever and adjustable along the lever vbetween the middle thereof and the end remote from the cam, a second lever pivoted about a iixed axis and jointedly connected to the first-mentioned lever. and means for guiding the fulcrum member in a rectilinear path.

4. A variable stroke mechanism comprising a rotarycam', a lever rocked by said" cam. a driven member freely bearing on one side of said lever at the middle thereof, a fulcrum member bearing on the opposite side of said lever and adjustable rectilinearly along the lever between the middle thereof and the end remote from the cam, and a second lever pivoted about a fixed axis and jointedly connected to the first-mentioned lever, said second lever being forked with the first-mentioned lever jointedly supported at one end between the arms of the fork, the other end of the first-mentioned lever resting freely on the fulcrum member.

5. A variable stroke mechanism comprising a rotary cam, a lever rocked by said cam, a driven member freely bearing on one side of said lever at the middle thereof, a fulcrum member bearing on the opposite side of said lever and adjustable rectilinearly along the lever between the middle thereof and the end remotefrom the cam, a second lever pivoted about a xed axis and jointedly connected to the first-mentioned lever, said second lever being forked with the first-mentioned lever jointedly supported at one end between the arms of the fork, the other end of the mst-mentioned lever resting freely on the fulcrum member, a shaft constituting the ilxed axis of said second lever, said shaft being parallel to the axis of rotation of the cam, an arm on said shaft, a' link connection between said arm and the movable fulcrum member, and means for .mar lPuur-ssamm. 

